The present invention relates to a cover for an open-body truck and particularly to a power-driven cover for such a truck.
Many states have now passed legislation requiring that the load be covered in open-body trucks and trailers. This is particularly important when a loose material is being carried by the truck which can be blown from the truck damaging oncoming and following automobiles as well as littering the highway.
In order to comply with the legislation, several different schemes have been developed for covering the truck loads. In one technique, a long piece of tubular material is extended from the front of the truck body to the rear. The cover is fastened to the tube and to one side of the truck. At one end of the tube, a large hand wheel is provided for rotating the tube and in turn unrolling the cover over the load. The tube rides along the top of the front and rear edges of the body and is rolled from side to side. The end of the tube remote from the hand wheel has a cable attached to a spring-bias means to assist in moving the remote end of the tube. While this device does indeed cover the open body of the truck, it does not work well with end dump trailers that have a tailgate. Also, it requires manual labor which can amount to enough time in many cases that the truck rates are affected substantially. Also, it is dangerous to have employees climbing up and down the trailer as many as 40 times per day to operate the cover. Also, since the tube rides along the front and rear edges of the truck body, any portion of the load extending above the edge has to be leveled by the truck driver before the cover can be put in place. The driver is not only placed at risk in climbing into and out of the truck but also in moving the load particularly if it is debris, for example, from the demolition of a building where broken glass, nails, and sheet metal expose the driver to the threat of severe physical injury.
In another attempt to contain the load in an open-body truck, a large U-shaped frame has been mounted so that it can pivot from a point centrally located near the bottom of the body of the truck midway between the front and rear. When the driver wishes to cover the load, he moves the frame causing the leading edge to rise high in the air over the load and then down to the rear of the open body. While this technique does protect the driver from having to climb into the body of the truck and level the load, it is subject to severe wind damage. It is now common practice when this technique is used to use an open mesh for the cover to allow the wind to freely pass through the cover. While this lessens the wind damage problem, it raises the problem of the load escaping through the mesh. The load can also escape over the trailer sides since the cover is attached to the front and rear of the body and does nothing to contain the sides.
In an attempt to solve the problem of the cover flapping in the wind and being subjected to tearing, another technique uses an accordion-type cover in which a cable supports the cover and guides it along each edge of the truck as the cover is pulled from the front of the truck body to the rear. While this technique does stiffen the center of the cover, it has been found that the entire cover is subject to being blown off the body due to the wind, therefore, also requiring an open mesh. Also, the cable on each side of the truck body is subject to damage by loading equipment. If the cable becomes damaged, the cover cannot be moved.
Each of the aforementioned techniques is found in common use on the highways today. As mentioned, each of these techniques is also subject to wind damage requiring the use of a mesh cover and those that require the cover to ride along the top edge of the open truck body present the problem of the driver having to move or level the load before the cover can be put in place.